Fixed angle centrifuge rotors are known. In such rotors, sample tube apertures of the rotor are disposed at a "fixed angle" in the normal range of 20.degree. to 34.degree.. Material to be centrifugated is placed in sample tubes within the sample tube apertures in the rotor body and spun at high speed. Classification of the material within the sample tubes occurs. At the end of such centrifugation, the classified sample is withdrawn and further processed.
It is known to make fixed angle rotors from composite materials. Further, it has been suggested to make such fixed angle rotors with chopped or discontinuous fibers. Unfortunately, fiber alignment of such chopped or discontinuous fibers has heretofore not been possible.
It is known that composite materials have anisotropic strength of material properties. Specifically, such materials have great resistance to tension, but are generally poor in resistance to all other modes of loading. In order to take maximum advantage of the tensile strength of such fibers, fiber alignment to a disposition where stresses of centrifugation can be resisted is required. This usually--but not always--requires that the fibers be aligned either normal to the spin axis or radially about the spin axis.
Compression molding of composite fiber parts is known. To date, such compression molding has not be applied for the manufacture of centrifuge rotors.